IPO, LTO: Plumb the summary from the LTO API into the pass manager.

[pcc]

Summary

Depends on D28424

Depends on D28546

[mehdi_amini]

LGTM.

llvm/include/llvm/LTO/LTOBackend.h

38

May not be straightforward to know why "a regular LTO backend" need a "CombinedIndex", so worth commenting.

llvm/include/llvm/Transforms/IPO/PassManagerBuilder.h

128

I'd add , for example the CFI and devirtualization type tests.

llvm/lib/LTO/LTOBackend.cpp

199

FIXME?

llvm/include/llvm/LTO/LTOBackend.h

 class BitcodeModule;
 class Error;
 class Module;
 class Target;
 
 namespace lto {
 
 /// Runs a regular LTO backend.
 Error backend(Config &C, AddStreamFn AddStream,
               unsigned ParallelCodeGenParallelismLevel,
-              std::unique_ptr<Module> M);
+              std::unique_ptr<Module> M, ModuleSummaryIndex &CombinedIndex);
 
 /// Runs a ThinLTO backend.
 Error thinBackend(Config &C, unsigned Task, AddStreamFn AddStream, Module &M,
                   ModuleSummaryIndex &CombinedIndex,
                   const FunctionImporter::ImportMapTy &ImportList,
                   const GVSummaryMapTy &DefinedGlobals,
                   MapVector<StringRef, BitcodeModule> &ModuleMap);
 }
 }
 
 #endif

llvm/include/llvm/Transforms/IPO/PassManagerBuilder.h

 #define LLVM_TRANSFORMS_IPO_PASSMANAGERBUILDER_H
 
 #include <functional>
 #include <memory>
 #include <string>
 #include <vector>
 
 namespace llvm {
+class ModuleSummaryIndex;
 class Pass;
 class TargetLibraryInfoImpl;
 class TargetMachine;
 
 // The old pass manager infrastructure is hidden in a legacy namespace now.
 namespace legacy {
 class FunctionPassManager;
 class PassManagerBase;
public:
   /// optimizer.  If this is non-null, it is added to both the function and
   /// per-module pass pipeline.
   TargetLibraryInfoImpl *LibraryInfo;
 
   /// Inliner - Specifies the inliner to use.  If this is non-null, it is
   /// added to the per-module passes.
   Pass *Inliner;
 
+  /// The module summary index to use for passing information between the
+  /// regular LTO phase and the thin LTO backends.
+  ModuleSummaryIndex *Summary = nullptr;
+
   bool DisableTailCalls;
   bool DisableUnitAtATime;
   bool DisableUnrollLoops;
   bool BBVectorize;
   bool SLPVectorize;
   bool LoopVectorize;
   bool RerollLoops;
   bool LoadCombine;

llvm/lib/LTO/LTO.cpp

for (const auto &R : GlobalResolutions) {
         GV->setLinkage(GlobalValue::InternalLinkage);
     }
 
     if (Conf.PostInternalizeModuleHook &&
         !Conf.PostInternalizeModuleHook(0, *RegularLTO.CombinedModule))
       return Error::success();
   }
   return backend(Conf, AddStream, RegularLTO.ParallelCodeGenParallelismLevel,
-                 std::move(RegularLTO.CombinedModule));
+                 std::move(RegularLTO.CombinedModule), ThinLTO.CombinedIndex);
 }
 
 /// This class defines the interface to the ThinLTO backend.
 class lto::ThinBackendProc {
 protected:
   Config &Conf;
   ModuleSummaryIndex &CombinedIndex;
   const StringMap<GVSummaryMapTy> &ModuleToDefinedGVSummaries;

llvm/lib/LTO/LTOBackend.cpp

report_fatal_error("unable to parse pass pipeline description: " +
                        PipelineDesc);
 
   if (!DisableVerify)
     MPM.addPass(VerifierPass());
   MPM.run(Mod, MAM);
 }
 
 static void runOldPMPasses(Config &Conf, Module &Mod, TargetMachine *TM,
-                           bool IsThinLTO) {
+                           bool IsThinLTO, ModuleSummaryIndex &CombinedIndex) {
   legacy::PassManager passes;
   passes.add(createTargetTransformInfoWrapperPass(TM->getTargetIRAnalysis()));
 
   PassManagerBuilder PMB;
   PMB.LibraryInfo = new TargetLibraryInfoImpl(Triple(TM->getTargetTriple()));
   PMB.Inliner = createFunctionInliningPass();
+  PMB.Summary = &CombinedIndex;
   // Unconditionally verify input since it is not verified before this
   // point and has unknown origin.
   PMB.VerifyInput = true;
   PMB.VerifyOutput = !Conf.DisableVerify;
   PMB.LoopVectorize = true;
   PMB.SLPVectorize = true;
   PMB.OptLevel = Conf.OptLevel;
   PMB.PGOSampleUse = Conf.SampleProfile;
   if (IsThinLTO)
     PMB.populateThinLTOPassManager(passes);
   else
     PMB.populateLTOPassManager(passes);
   passes.run(Mod);
 }
 
 bool opt(Config &Conf, TargetMachine *TM, unsigned Task, Module &Mod,
-         bool IsThinLTO) {
+         bool IsThinLTO, ModuleSummaryIndex &CombinedIndex) {
   if (Conf.OptPipeline.empty())
-    runOldPMPasses(Conf, Mod, TM, IsThinLTO);
+    runOldPMPasses(Conf, Mod, TM, IsThinLTO, CombinedIndex);
   else
     runNewPMCustomPasses(Mod, TM, Conf.OptPipeline, Conf.AAPipeline,
                          Conf.DisableVerify);
   return !Conf.PostOptModuleHook || Conf.PostOptModuleHook(Task, Mod);
 }
 
 void codegen(Config &Conf, TargetMachine *TM, AddStreamFn AddStream,
              unsigned Task, Module &Mod) {
   if (Conf.PreCodeGenModuleHook && !Conf.PreCodeGenModuleHook(Task, Mod))
     return;
ModuleSymbolTable::CollectAsmSymbols(
         if (Flags & object::BasicSymbolRef::SF_Undefined)
           AsmUndefinedRefs.insert(Name);
       });
   updateCompilerUsed(Mod, TM, AsmUndefinedRefs);
 }
 
 Error lto::backend(Config &C, AddStreamFn AddStream,
                    unsigned ParallelCodeGenParallelismLevel,
-                   std::unique_ptr<Module> Mod) {
+                   std::unique_ptr<Module> Mod,
+                   ModuleSummaryIndex &CombinedIndex) {
   Expected<const Target *> TOrErr = initAndLookupTarget(C, *Mod);
   if (!TOrErr)
     return TOrErr.takeError();
 
   std::unique_ptr<TargetMachine> TM =
       createTargetMachine(C, Mod->getTargetTriple(), *TOrErr);
 
   handleAsmUndefinedRefs(*Mod, *TM);
 
   if (!C.CodeGenOnly)
-    if (!opt(C, TM.get(), 0, *Mod, /*IsThinLTO=*/false))
+    if (!opt(C, TM.get(), 0, *Mod, /*IsThinLTO=*/false, CombinedIndex))
       return Error::success();
 
   if (ParallelCodeGenParallelismLevel == 1) {
     codegen(C, TM.get(), AddStream, 0, *Mod);
   } else {
     splitCodeGen(C, TM.get(), AddStream, ParallelCodeGenParallelismLevel,
                  std::move(Mod));
   }
Error lto::thinBackend(Config &Conf, unsigned Task, AddStreamFn AddStream,
 
   FunctionImporter Importer(CombinedIndex, ModuleLoader);
   if (Error Err = Importer.importFunctions(Mod, ImportList).takeError())
     return Err;
 
   if (Conf.PostImportModuleHook && !Conf.PostImportModuleHook(Task, Mod))
     return Error::success();
 
-  if (!opt(Conf, TM.get(), Task, Mod, /*IsThinLTO=*/true))
+  if (!opt(Conf, TM.get(), Task, Mod, /*IsThinLTO=*/true, CombinedIndex))
     return Error::success();
 
   codegen(Conf, TM.get(), AddStream, Task, Mod);
   return Error::success();
 }

llvm/lib/Transforms/IPO/PassManagerBuilder.cpp

 
 void PassManagerBuilder::populateThinLTOPassManager(
     legacy::PassManagerBase &PM) {
   PerformThinLTO = true;
 
   if (VerifyInput)
     PM.add(createVerifierPass());
 
+  if (Summary)
+    PM.add(
+        createLowerTypeTestsPass(LowerTypeTestsSummaryAction::Import, Summary));
+
   populateModulePassManager(PM);
 
   if (VerifyOutput)
     PM.add(createVerifierPass());
   PerformThinLTO = false;
 }
 
 void PassManagerBuilder::populateLTOPassManager(legacy::PassManagerBase &PM) {
   if (LibraryInfo)
     PM.add(new TargetLibraryInfoWrapperPass(*LibraryInfo));
 
   if (VerifyInput)
     PM.add(createVerifierPass());
 
   if (OptLevel != 0)
     addLTOOptimizationPasses(PM);
 
   // Create a function that performs CFI checks for cross-DSO calls with targets
   // in the current module.
   PM.add(createCrossDSOCFIPass());
 
   // Lower type metadata and the type.test intrinsic. This pass supports Clang's
   // control flow integrity mechanisms (-fsanitize=cfi*) and needs to run at
   // link time if CFI is enabled. The pass does nothing if CFI is disabled.
-  PM.add(createLowerTypeTestsPass(LowerTypeTestsSummaryAction::None,
-                                  /*Summary=*/nullptr));
+  PM.add(createLowerTypeTestsPass(Summary ? LowerTypeTestsSummaryAction::Export
+                                          : LowerTypeTestsSummaryAction::None,
+                                  Summary));
 
   if (OptLevel != 0)
     addLateLTOOptimizationPasses(PM);
 
   if (VerifyOutput)
     PM.add(createVerifierPass());
 }
 

llvm/test/LTO/Resolution/X86/lowertypetests.ll

+; RUN: opt -thinlto-bc -o %t %s
+; RUN: llvm-lto2 -r %t,f,plx -r %t,foo,lx -r %t,foo,plx -o %t1 %t
+; RUN: llvm-nm %t1.0 | FileCheck --prefix=MERGED %s
+; RUN: llvm-nm %t1.1 | FileCheck %s
+
+; MERGED: R __typeid_foo_global_addr
+; CHECK: U __typeid_foo_global_addr
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+@foo = global i32 0, !type !0
+
+define i1 @f(i8* %ptr) {
+  %p = call i1 @llvm.type.test(i8* %ptr, metadata !"foo")
+  ret i1 %p
+}
+
+declare i1 @llvm.type.test(i8* %ptr, metadata %typeid) nounwind readnone
+
+!0 = !{i32 0, !"foo"}